CF5074A

SEIKO NPC CORPORATION —5

SWITCHING CHARACTERISTICS

FUNCTIONAL DESCRIPTION

Standby Function

When INHN goes LOW, the device is in standby mode. The Q output becomes high impedance and the oscilla-

tor circuit continues running.

Power-saving Pull-up Resistor

The INHN pin pull-up resistance changes in response to the input level (HIGH or LOW). When INHN is tied

LOW, the pull-up resistance becomes large, reducing the current consumed by the resistance. When INHN is

left open, the pull-up resistance becomes small, such that even if the input is affected by external noise the out-

puts are stable due to INHN being tied HIGH by the pull-up resistor.

Oscillation Start-up Detector Function

The devices also feature an oscillation start-up detector circuit. This circuit functions to disable the outputs

until the oscillation starts. This prevents unstable oscillator output at oscillator start-up when power is applied.

Parameter

Symbol

Conditions

Rating

Unit

Min

Typ

Max

Output rise time

Measurement circuit 2, load circuit 1,

–

2.5

4

ns

Output fall time

Measurement circuit 2, load circuit 1,

–

2.5

4

ns

Output duty cycle

Duty

Measurement circuit 2,

load circuit 1, Ta = 25

°C,

40

50

60

%

45

50

55

%

Output disable delay time

Measurement circuit 5, load circuit 1,

Ta = 25

–

–

100

ns

Output enable delay time

–

–

100

ns

INHN

Q

Oscillator

HIGH (or open)

Operating

LOW

High impedance

Operating